Velocity

[mathxyz]

A ball is dropped from the upper observation deck of the CN Tower in Toronto, 450 meters above the ground. Find the velocity of the ball after 5 seconds.

Is there a formula I can use to find the velocity after 5 seconds?

 

[ChaoticLlama]

A ball is dropped from the upper observation deck of the CN Tower in Toronto, 450 meters above the ground. Find the velocity of the ball after 5 seconds.

Is there a formula I can use to find the velocity after 5 seconds?

think about this for a second, does what height you are at affect how an object accelerates? No. So 450m is usless.

This is a standard physics kinematics problem. Set up your givens, and solve for the unknown.

V1 = 0m/s
V2 = ?
a = 9.8m/s²
t = 5s

you should be able to take it from here.

 

[tkhunny]

Does what height you are at affect how an object accelerates? No. So 450m is useless.

CL:

Try it with t = 10 seconds and see if 450m makes any difference. :wink:

 

[Guest]

Is there a formula I can use to find the velocity after 5 seconds?

Yes, and you can figure it out.

When an object is in free-fall (falling freely) near the surface of the earth, which this ball is, its acceleration is about 9.8 meters per second per second downward. That means that after each second, its velocity increases by 9.8 meters per second downward. When it started falling, its velocity was zero. It wasn't thrown or anything--just dropped. It increases by 9.8 meters per second downward every second, so after 5 seconds, what is its velocity?

 

[mathxyz]

ok

Great notes. I will study and solve similar questions.

 

[ChaoticLlama]

Does what height you are at affect how an object accelerates? No. So 450m is useless.

CL:

Try it with t = 10 seconds and see if 450m makes any difference. :wink:

Well, who would've thought it would hit the ground??? :roll:

Thanks for pointing that out. So the 450m is not completely useless.

 

[tkhunny]

No worries. Those Canadians are always building things at ground level.

Note to Student: See how important Domain considerations are? There's always a difference between the mathematics and the real world.

 

[Denis]

The CN tower was built to...

Well, by the 10 seconds mark, how often will the ball have bounced?
(assuming it always hits the same asphalt spot!)

Question 2: assume when the ball first hits the ground, gravity disappears,
and the ball bounces up at same speed that it was when it hit the ground:
when will the ball dropper get the ball back?

 

[tkhunny]

Does the ball dropper get gravity back when catching the ball? That could be a problem unless the ball dropper is hanging on tight.

 

[Denis]

No problems: they hired a retired Toronto Blue Jays catcher...

 

[mathxyz]

hey

Denis,

Who's the retired Blue Jays Catcher?